SX8651
ADVANCED COMMUNICATIONS & SENSING
4
Multitouch 4-wire Resistive Touchscreen
Controller with 15kV ESD Protection
DATASHEET
KEY PRODUCT FEATURES
Extremely Low Power Consumption: 23uA@1.8V 8kSPS
Superior On-chip ESD Protection
±15kV HBM (X+,X-,Y+,Y-)
±2kV CDM
±25kV Air Gap Discharge
±15kV Contact Discharge
±300V MM
Compatible with a Wide Range of 4-wire Resistive
Touchscreen for Single/Multi-touch Operation
Integrated Preprocessing Block to Reduce Host Loading
and Bus Activity
Four User Programmable Operation Modes provides
Flexibility to address Different Application Needs
Manual, Automatic, Pen Detect, Pen Trigger
High Precision 12-bit Resolution
Low Noise Ratiometric Conversion
Selectable Polling or Interrupt Modes
Touch Pressure Measurement
400kHz Fast-Mode I²C Interface
Hardware Reset & I²C Software Reset
-40° to 85° Operation
C
C
Pin-compatible with SX8650
Android and Linux Driver Support Available
12-LD DFN Package / 12-Ball WLCSP Package
RoHS, WEEE, HF and pb free
GENERAL DESCRIPTION
The SX8651 is a multitouch controller that enables a
completely different user interaction with 4-wire resistive
touchscreen. It enables detection of 2 fingers on the
touchscreen and several gestures like rotation and pinch/
stretch.
This ultra low power touchscreen controller has been
optimized for portable equipment where power and board-
space are at a premium.
It incorporates a highly accurate 12-bit ADC for data
conversion and operates from a single 1.65 to 3.7V supply
voltage.
The SX8651 features a built-in preprocessing algorithm for
data measurements, which greatly reduces the host
processing overhead and bus activity. This complete
touchscreen solution includes four user-selectable
operation modes which offer programmability on different
configurations such as conversion rate and settling time,
thus enable optimization in throughput and power
consumption for a wide range of touch sensing applications.
The touch screen inputs have been specially designed to
provide robust on-chip ESD protection of up to ±15kV in
both HBM and Contact Discharge, and eliminates the need
for external protection devices.
The SX8651 is offered in two tiny packages: 3.0 mm x
3.0 mm DFN and a 1.5 mm x 2.0 mm wafer-level chip-scale
package (WLCSP).
APPLICATIONS
Portable Equipment
Mobile Communication Devices
Cell phone, PDA, MP3, GPS, DSC
Touch Screen Monitors
ORDERING INFORMATION
Part Number
SX8651ICSTRT
1
SX8651IWLTRT
1
1. 3000 Units / reel
Package
(Dimension in mm)
12 - Ball WLCSP
(1.5 x 2.0)
12 - Lead DFN
(3.0 x 3.0)
Marking
FD77
FD77
Block Diagram
VDD
C o n tro l
SX8651
AUX
A0
X+
PO R
Y+
X-
Y-
GND
T ou ch
S c re e n
In te rfa c e
in
V re f
re f-
O SC
I2 C
NRST
SCL
HOST
re f+
A D C out
SDA
D ig ita l
F ilte r
N IR Q
Revision V1.5/December 2010
©2010 Semtech Corp.
Page 1
www.semtech.com
SX8651
ADVANCED COMMUNICATIONS & SENSING
Table of contents
Section
Page
DATASHEET
1.
General Description ................................................................................................................................................. 4
1.1.
1.2.
1.3.
1.4.
DFN Pinout Diagram and Marking Information (Top View).............................................................................. 4
WLCSP Pinout Diagram and Marking Information (Top View) ........................................................................ 4
Pin Description................................................................................................................................................. 5
Simplified Block Diagram ................................................................................................................................. 5
Recommended Operating Conditions.............................................................................................................. 6
Thermal Characteristics ................................................................................................................................... 6
Electrical Specifications ................................................................................................................................... 7
Host Interface Specifications ........................................................................................................................... 9
Host Interface Timing Waveforms.................................................................................................................. 10
Typical Operating Characteristics .................................................................................................................. 11
General Introduction ..................................................................................................................................... 13
Channel Pins.................................................................................................................................................. 13
X+, X-, Y+. Y- .......................................................................................................................................... 13
AUX ......................................................................................................................................................... 13
NIRQ ....................................................................................................................................................... 14
SCL ......................................................................................................................................................... 14
SDA ......................................................................................................................................................... 14
A0 ............................................................................................................................................................ 15
NRST ...................................................................................................................................................... 15
VDD......................................................................................................................................................... 15
GND ........................................................................................................................................................ 15
2.
Electrical Characteristics ......................................................................................................................................... 6
2.1.
2.2.
2.3.
2.4.
2.5.
2.6.
3.
Functional Description ........................................................................................................................................... 13
3.1.
3.2.
3.2.1.
3.2.2.
3.3.
3.3.1.
3.3.2.
3.3.3.
3.3.4.
3.3.5.
3.4.
3.4.1.
3.4.2.
4.
4.1.
4.2.
4.3.
4.4.
4.5.
5.
5.1.
Host Interface and Control Pins ..................................................................................................................... 14
Power Management Pins............................................................................................................................... 15
Detailed Description............................................................................................................................................... 16
Touch Screen Operation................................................................................................................................ 16
Coordinates Measurement............................................................................................................................. 17
Pressure Measurement.................................................................................................................................. 17
Pen Detection ................................................................................................................................................ 18
Double touch measurement........................................................................................................................... 19
Host Interface and Control ............................................................................................................................. 20
I2C Address ............................................................................................................................................ 20
I2C Write Registers ................................................................................................................................. 21
I2C Read Registers ................................................................................................................................. 21
I2C Host Commands ............................................................................................................................... 22
I2C Read Channels ................................................................................................................................ 23
Page 2
Data Processing .................................................................................................................................................... 20
5.1.1.
5.1.2.
5.1.3.
5.1.4.
5.1.5.
Revision V1.5/December 2010
©2010 Semtech Corp.
www.semtech.com
SX8651
ADVANCED COMMUNICATIONS & SENSING
Table of contents
Section
Page
DATASHEET
5.1.6.
5.1.7.
5.2.
5.3.
5.4.
5.5.
5.6.
6.
6.1.
6.2.
6.3.
6.4.
7.
7.1.
7.2.
7.3.
Data Channel Format ............................................................................................................................. 24
Invalid Qualified Data .............................................................................................................................. 24
I2C Register Map .......................................................................................................................................... 24
Host Control Writing....................................................................................................................................... 25
Host Commands ............................................................................................................................................ 27
Power-Up ....................................................................................................................................................... 28
Reset.............................................................................................................................................................. 28
Manual Mode ................................................................................................................................................. 29
Automatic mode ............................................................................................................................................. 30
PENDET Mode .............................................................................................................................................. 31
PENTRIG Mode ............................................................................................................................................. 31
Acquisition Setup ........................................................................................................................................... 32
Channel Selection.......................................................................................................................................... 32
Noise Reduction............................................................................................................................................. 32
POWDLY................................................................................................................................................. 32
SETDLY .................................................................................................................................................. 32
AUX Input ................................................................................................................................................ 33
Modes of Operation .............................................................................................................................................. 29
Application Information .......................................................................................................................................... 32
7.3.1.
7.3.2.
7.3.3.
7.4.
7.5.
Interrupt Generation....................................................................................................................................... 33
Coordinate Throughput Rate ......................................................................................................................... 33
I2C Communication Time........................................................................................................................ 33
Conversion Time ..................................................................................................................................... 33
AUTO MODE .......................................................................................................................................... 34
7.5.1.
7.5.2.
7.5.3.
7.6.
7.7.
8.
8.1.
8.2.
9.
9.1.
9.2.
ESD event...................................................................................................................................................... 34
Application Schematic.................................................................................................................................... 35
Zoom Gesture ................................................................................................................................................ 35
Rotate Gesture............................................................................................................................................... 35
DFN Package................................................................................................................................................. 36
WLCSP Package ........................................................................................................................................... 38
Multi-Touch Gestures ............................................................................................................................................ 35
Packaging Information ........................................................................................................................................... 36
Revision V1.5/December 2010
©2010 Semtech Corp.
Page 3
www.semtech.com
SX8651
ADVANCED COMMUNICATIONS & SENSING
Multitouch 4-wire Resistive Touchscreen
Controller with 15kV ESD Protection
DATASHEET
1. General Description
1.1. DFN Pinout Diagram and Marking Information (Top View)
VDD
X+
Y+
X-
Y-
GND
1
2
3
4
5
6
12
AUX
A0
NRST
SCL
SDA
NIRQ
FD77
YYWW
SX8651
TOP VIEW
13
11
10
9
8
7
XXXX
PIN 1
IDENTIFIER
Figure 1. SX8651 DFN Top View, Pad on Bottom Side
The Device marking and
YYWW: Date Code
XXXXX: Lot Number
1.2. WLCSP Pinout Diagram and Marking Information (Top View)
X+
3
VDD
2
AUX
1
NIRQ
SDA
SCL
A0
NRST
GND
Y+
X-
Y-
FD 77
A
B
C
D
SX8651 TOP VIEW
solder bumps on bottom side
BALL A1
ID EN TIFIER
Figure 2. SX8651 WLCSP Top View, Solder Bumps on Bottom Side
YYWW: Date Code
XXXXX: Lot Number
Revision V1.5/December 2010
©2010 Semtech Corp.
Page 4
www.semtech.com
SX8651
ADVANCED COMMUNICATIONS & SENSING
1.3. Pin Description
Pin Number
#
DFN
1
2
3
4
5
6
7
8
9
10
11
12
13
WLCSP
A2
A3
B3
C3
D3
D2
B1
C1
D1
C2
B2
A1
VDD
X+
Y+
X-
Y-
GND
NIRQ
SDA
SCL
NRST
A0
AUX
GND
Power
Analog
Analog
Analog
Analog
Ground
Digital Output / Open Drain Output
Digital Input / Open Drain Output
Digital Input / Open Drain Output
Digital Input / Output
Digital Input
Digital Input/Analog Input
Ground
Input power supply connect to a 0.1uF capacitor to GND
X+ channel input
Y+ channel input
X- channel input
Y- channel input
Ground
Interrupt output, active low. Need external pull-up resistor
I2C data input/output
I2C clock, input/output
Reset Input, active low. Need external 50k pull-up resistor
I2C slave address selection input
Analog auxiliary input or conversion synchronization
Die attach paddle, connect to Ground
Name
Type
Description
Multitouch 4-wire Resistive Touchscreen
Controller with 15kV ESD Protection
DATASHEET
Table 1. Pin description
1.4. Simplified Block Diagram
The SX8651 simplified block diagram is shown in Figure 3.
VDD
Control
X+
SX8651
AUX
A0
Y+
POR
X-
Touch
Screen
Interface
ref+
Vref
in
ref-
ADC out
Digital
Filter
OSC
I2C
NRST
SCL
Y-
GND
SDA
NIRQ
Figure 3. Simplified block diagram of the SX8651
Revision V1.5/December 2010
©2010 Semtech Corp.
Page 5
www.semtech.com
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